Out of curiosity, how well do those C-Products mags handle in terms of jams and also holding open the bolt after the last round?

sorry, just saw your question. i had to play with my ejector for the c products mags to run right. once i found the sweet spot they fed and cycled rounds correctly. my bolt hold open function isn't doing so great right now though. it barely keeps open but wants to slam closed any chance it gets. its just a matter of adjustment.